Risk assessment of cognitive impairment at 2 years of age in infants born extremely preterm using the INTERGROWTH-21st growth standards

Abstract

Objective To assess the risk of cognitive impairment among infants born extremely preterm using the INTERGROWTH-21st standards. Study design We analyzed anthropometric data at birth and 36 weeks postmenstrual age (PMA) from infants born extremely preterm (24-26 weeks of gestation) admitted to US neonatal units between 2008 and 2018. To determine INTERGROWTH-21st z-score values that indicate an increased risk of cognitive impairment at 2 years of age (Bayley cognitive score <85), we employed classification and regression trees and redefined growth failure (weight, length, and head circumference z-scores at 36 weeks PMA) and growth faltering (weight, length, and head circumference z-score declines from birth to 36 weeks PMA). Results Among 5393 infants with a mean gestational age of 25 weeks, growth failure defined as a weight z-score of-1.8 or below at 36 weeks PMA and growth faltering defined as a weight z-score decline of 1.1 or greater from birth to 36 weeks PMA indicated a higher likelihood of cognitive impairment. A length z-score less than-1 at 36 weeks PMA had the highest sensitivity to detect cognitive impairment at 2 years (80%). A head circumference z-score decline of 2.43 or greater from birth to 36 weeks PMA had the highest specificity (86%). Standard definitions had fair to low sensitivity and specificity for risk detection of cognitive impairment. Conclusions Length and head circumference z-scores had the highest sensitivity and specificity for risk detection of cognitive impairment. Monitoring these growth parameters could guide earlier individualized interventions with potential to reduce cognitive impairment.